Positive Electrode Rinsing Chemistry for Residual Lithium Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for preparing nickel-based positive electrode active materials result in residual lithium byproducts on the surface, leading to performance degradation and stability issues in batteries, and the use of large amounts of deionized water for rinsing exacerbates surface degradation.
Innovation Solution
A rinsing process using a trace amount of LiOH, NaOH, or KOH additives in a pH-adjusted rinsing solution (pH 12 or more) minimizes surface degradation and effectively controls residual lithium during the preparation of lithium transition metal oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If deionized water or distilled water is used in the rinsing process, then residual lithium can be removed, but the surface of the positive electrode active material is degraded
Solution Approach 1:
The patent changes the chemical parameters of the rinsing solution by adjusting pH to 12 or higher and adding specific additives (LiOH, NaOH, or KOH at 3,000-18,000 ppm). This parameter change allows effective lithium removal while preventing surface degradation that occurs with neutral pH water rinsing.
Solution Approach 2:
The patent introduces an intermediary substance (additive such as LiOH, NaOH, or KOH) into the rinsing solution. This intermediary mediates between the need to remove lithium and the need to protect the material surface, enabling both goals to be achieved simultaneously.
2Quantity of substance
If a large amount of deionized water is used in the rinsing process, then residual lithium control is improved, but process problems occur and surface degradation is exacerbated
Solution Approach 1:
By changing the chemical composition parameters (pH and additive concentration) of the rinsing solution, the patent achieves effective lithium control with reduced water consumption, thereby improving process efficiency and eliminating the need for large volumes of rinsing water.
3Quantity of substance
If conventional rinsing with deionized water is used, then residual lithium is removed, but battery performance degrades due to surface degradation
Solution Approach 1:
The patent modifies the rinsing solution parameters (pH ≥12 and additive concentration of 3,000-18,000 ppm) to achieve a dual effect: removing residual lithium while protecting the material surface. This prevents the surface degradation that leads to battery performance deterioration.
Solution Approach 2:
The patent converts the potentially harmful effect of water rinsing (which causes surface degradation) into a beneficial process by adjusting the chemical parameters. The modified rinsing solution now provides both cleaning and protection functions, turning a harmful process into a beneficial one.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method reduces rinsing solution usage, minimizes surface degradation, and enhances battery performance by effectively removing residual lithium, thereby improving long-term stability and capacity retention.
Implementation Method 1
mixing the lithium transition metal oxide and a rinsing solution and performing rinsing and drying
Implementation Method 2
the rinsing solution includes one or more additive of LiOH, NaOH, or KOH, the additive is included in an amount of 3,000 ppm to 18,000 ppm relative to the lithium transition metal oxide in the rinsing solution, and the rinsing solution has a pH of 12 or more
Data Source
AI summary
The method of preparing a positive electrode capable of reducing the usage amount of a rinsing solution, and minimizing the surface degradation of a positive electrode active material is provided. A method of preparing a positive electrode active material includes: (A) preparing a lithium transition metal oxide; and (B) mixing the lithium transition metal oxide and a rinsing solution and performing rinsing and drying, wherein the rinsing solution includes one or more additive of LiOH, NaOH, or KOH, the additive is included in an amount of 3,000 ppm to 18,000 ppm relative to the lithium transition metal oxide in the rinsing solution, and the rinsing solution has a pH of 12 or more.